User-Meeting PyRolL 2024

Date: 30th August 2024
Time: 08:00 - 12:00
Participants:

• G. Rothenbucher (GR)
• M. Molter (MM)
• C. Fasching (CF)
• M. Liskow (ML)
• C. Schäfer (CS)
• M. Schmidtchen (MSc)
• M. Weiner (MW)
• M. Stirl (MS)
• J. Mantel (JM)
• K. Hasan (KH)

Introduction

• Several new Packages, first funded Project with PyRolL, …

• Question CR In several Thesis at our Institute we combined several Packages with PyRolL - Like PyCalphad in Thesis by W. Tell (CCT-Diagrams, …):

  • MM: depends on usage of PyRolL - so depends on who you ask. R&D departments may want that
  • CR: several Companies have their own material Databases. Should we invest time to support that or to give examples:
    • MSc: We cannot give out all datasets - only from publicly funded
    • GR: contact JMatPro representative to get to know what needs to be supported - JMatPro has example Datasets and we should consider to have the ability to support those
      • but we shouldnt need to necessarily support all Materials or Invest too much Time into what goes beyond that
      • https://matplus.eu/de/
  • CR: What about other Packages like MatCalc or Thermocalc?
    • Matcalc better as the contact is better - and they want to work with us
    • We should rather focus on supporting that and giving examples - what goes beyond is in the responsibility of the user

• Question CR should we continue to give examples like the recent velocity calculation in Jupyter Notebooks?:

  • Talk about interstand tensions and their relevancy for rolling (came to that topic as we recently created a notebook for that)
  • CR: We could provide a notebook that shows an example for calculating interstand tension and adjusting stand RPMs depending on changes to the process
  • Also we require the Pillar Model to be accurate for this:
    • Currently we have no actually working spreading model for the pillar model (except for maybe Geuze) as they are all one-step models
    • MSc: some publication got their stress distributions from FEMs

Master Thesis KH

• 5-pass ThreeRollPass system is to be optimised using genetic algorithms (SciPy)
  • optimisation regarding the inscribed circle diameter
  • –> see jupyter notebook

Example Notebook MM & GR

• In recent meetings (last Kalibreurstag 2023, Kick-Off Validation funding) several shortcomings of the current PyRolL version came up.
• Shortcomings:
  • Python based (hard to get into)
  • html export not optimised for use in companies
  • SI units and not the typical units (mm, °C, …)
• Notebook:
  • basic idea: only one cell to edit, rest is calculating "by itself" without the need for input from user
  • additional Packages or usages:
    • python-pptx
    • import from an excel (which contains roll/ groove contours)
  • Input:
    • groove list
      • specifies roll or groove label for input from the excel
      • excel can also diferentiate between Two-/ ThreeRollPasses
    • material
      • specified in seperate file
      • PyRolL should support import of several datatypes to import material parameters im companies
    • hot/ cold measure and thermal expansion factor
  • MM: should more input parameters be already present in the excel table?
    • MW: not a problem if more is in the excel sheet, as all values can be changed later on anyways if one wants to test different setups
  • Conversion file
    • converts non SI units to SI (or the other way)
  • GR: Maybe create a wrapper function for all the in profiles? so one doesnt need to support all in-profile types in the notebook.
    • MW: we currently do it this way so that ther is Tab-completion but a wrapper function could be possible
  • import from dataframe to PyRolL pass sequence structure using PyRolL-from-dict package
  • MM: Maybe give possibility to supply different friction factors for different stands?
    • difference between carbide rolls or cast iron rolls
  • Transport lengths in array
  • GR possibility for the customer to provide Meta-information like:
    • define Drivetrain
    • Stand layout and distances
    • MW: we thought about giving a package for drivetrain which can take gearratios and others and then output efficiencies
      • or to give errors if my powers or forces exceed the capabilities of my machinery
  • tension and velocity calculations
    • notebook assumes no tension
  • export to dataframe and now one can do with it whatever they want
    • conversion back from SI units
    • plotting, pandas analysis functions
  • modify_df function:
    • optimises output values for later use
    • horizontal/ vertical orientation
    • rename inscribed circle diameter to DSA
  • 3D plot of entire sequence
    • currently matplotlib
    • maybe use plotly?!
  • plot to an animation with one frame for each pass
  • export to pptx:
    • export to tables
    • easy to setup plots
    • several subplots (boxplots) for typical rolling/ forming parameters
    • comparison of actual plant values to simulated ones
    • the roll working diameter PyRolL calculates is very good (its just the centre of gravity of the roll contour substractes from the nominal diameter)
  • comparison of values from a chinese paper to PyRolL
    • also plots contour in cylinder-coordinates
    • maybe PyRolL should support that conversion?
  • GR: Hill model with additional factor gives the best fit
  • MM:
    • in ThreeRollPasses Marini spreading model is sometimes significantly better than Wusatowski
    • but in TwoRollPasses and some ThreeRollPasses is minimal again
  • GR suggestion: Provide contact contour as Polygon, as one currently has to use the zouhar factors to plot it
  • there is no global scaling currently
    • so each roll pass plot scales scales depending on itself and passes furhter back in the pass sequence get larger and larger
    • maybe give ability to provide a global scaling factor depending on the largest roll pass so that they are easily comparable

MM comparison of examples to different simulation softwares

• comparison of Q-Kaliber, Q-Form, MPC, PyRolL
• for PassSequence of MM
• winconp
  • what values should also be given by pyroll
  • (tonnage per hour, stand elasticity, productivity values)

MW assymetric rolling

• probably in PyRolL 3.0 or 2.2 we will implement support for different rolls (for example: different upper/ lower roll in TwoRollPasses)
• needed entirely different structure in base PyRolL code –> therefore new version

End discussion

• Wishes for development 2025:
  • GR: RPM calculation from profile velocities and interstand tension
  • CR: velocity differences previous - next stand as a r-factor (give to pyroll)
  • pillar model:
    • not too necessary, especially for three-roll-pass
    • but it gives real profile contour
    • or realise the profile contour with another model
• Future of Pyroll:
  • discussion on how to best proceed since next year MW, CR will have little time for Pyroll